Skip to content

Commit

Permalink
UHCI: fix port resume problem
Browse files Browse the repository at this point in the history
This patch (as863) fixes a problem encountered sometimes when resuming
a port on a UHCI controller.  The hardware may turn off the
Resume-Detect bit before turning off the Suspend bit, leading usbcore
to think that the port is still suspended and the resume has failed.
The patch makes uhci_finish_suspend() wait until both bits are safely
off.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  • Loading branch information
Alan Stern authored and Greg Kroah-Hartman committed Mar 10, 2007
1 parent 97b9eb9 commit 8801815
Showing 1 changed file with 7 additions and 4 deletions.
11 changes: 7 additions & 4 deletions drivers/usb/host/uhci-hub.c
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,9 @@ static __u8 root_hub_hub_des[] =
/* status change bits: nonzero writes will clear */
#define RWC_BITS (USBPORTSC_OCC | USBPORTSC_PEC | USBPORTSC_CSC)

/* suspend/resume bits: port suspended or port resuming */
#define SUSPEND_BITS (USBPORTSC_SUSP | USBPORTSC_RD)

/* A port that either is connected or has a changed-bit set will prevent
* us from AUTO_STOPPING.
*/
Expand Down Expand Up @@ -96,8 +99,8 @@ static void uhci_finish_suspend(struct uhci_hcd *uhci, int port,
int status;
int i;

if (inw(port_addr) & (USBPORTSC_SUSP | USBPORTSC_RD)) {
CLR_RH_PORTSTAT(USBPORTSC_SUSP | USBPORTSC_RD);
if (inw(port_addr) & SUSPEND_BITS) {
CLR_RH_PORTSTAT(SUSPEND_BITS);
if (test_bit(port, &uhci->resuming_ports))
set_bit(port, &uhci->port_c_suspend);

Expand All @@ -107,7 +110,7 @@ static void uhci_finish_suspend(struct uhci_hcd *uhci, int port,
* Experiments show that some controllers take longer, so
* we'll poll for completion. */
for (i = 0; i < 10; ++i) {
if (!(inw(port_addr) & USBPORTSC_RD))
if (!(inw(port_addr) & SUSPEND_BITS))
break;
udelay(1);
}
Expand Down Expand Up @@ -289,7 +292,7 @@ static int uhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
wPortStatus |= USB_PORT_STAT_CONNECTION;
if (status & USBPORTSC_PE) {
wPortStatus |= USB_PORT_STAT_ENABLE;
if (status & (USBPORTSC_SUSP | USBPORTSC_RD))
if (status & SUSPEND_BITS)
wPortStatus |= USB_PORT_STAT_SUSPEND;
}
if (status & USBPORTSC_OC)
Expand Down

0 comments on commit 8801815

Please sign in to comment.